[148.05] Quantifying the Bull's-Eye Effect: Thick Slices

We present the results of an investigation into the method
proposed by Melott et al. (1998) for quantifying the
bull's-eye effect in maps of large scale structure. The
bull's-eye effect is a distortion in redshift-space produced
by peculiar velocities. Structures lying across the line of
sight are enhanced, but structures lying along the line of
sight are not, producing an impression of walls ringing the
observer (Praton, Melott, & McKee 1997), much like those
seen in recent large scale surveys. Simulations show that
the strength of the pattern varies with initial cosmological
conditions; thus, our interest in developing a reliable way
to quantify the effect, as a possible way to independently
determine parameters such as \Omega.

Thomas et al. (2004) showed that the proposed method can
successfully distinguish between high and low \Omega
simulations, independent of bias, for thin slices in the
cartesian limit. We carry that investigation further,
looking at thick slices in the cartesian limit. Since the
bull's-eye pattern grows stronger as slice thickness
increases (Praton, Melott, & Peterson 1997), we expect the
method to become more reliable. Instead, we find the
opposite. We discuss the reasons, as well as results from
one or two possible alternatives.